sys/src/libregexp/rregexec.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <regexp.h>
   4 #include "regimpl.h"
   5
   6 typedef struct RethreadQ RethreadQ;
   7 struct RethreadQ {
   8         Rethread *head;
   9         Rethread **tail;
  10 };
  11
  12 int
  13 rregexec(Reprog *p, Rune *str, Resub *sem, int msize)
  14 {
  15         RethreadQ lists[2], *clist, *nlist, *tmp;
  16         Rethread *t, *next, *pool, *avail;
  17         Reinst *ci;
  18         Rune *rsp, *rep, endr, r;
  19         int matchgen, gen;
  20
  21         if(msize > NSUBEXPM)
  22                 msize = NSUBEXPM;
  23
  24         if(p->startinst->gen != 0) {
  25                 for(ci = p->startinst; ci < p->startinst + p->len; ci++)
  26                         ci->gen = 0;
  27         }
  28
  29         memset(p->threads, 0, sizeof(Rethread)*p->nthr);
  30
  31         clist = lists;
  32         clist->head = nil;
  33         clist->tail = &clist->head;
  34         nlist = lists + 1;
  35         nlist->head = nil;
  36         nlist->tail = &nlist->head;
  37
  38         pool = p->threads;
  39         avail = nil;
  40
  41         gen = matchgen = 0;
  42         rsp = str;
  43         rep = nil;
  44         endr = L'\0';
  45         if(sem != nil && msize > 0) {
  46                 if(sem->rsp != nil)
  47                         rsp = sem->rsp;
  48                 if(sem->rep != nil && *sem->rep != L'\0') {
  49                         rep = sem->rep;
  50                         endr = *sem->rep;
  51                         *sem->rep = '\0';
  52                 }
  53         }
  54         for(r = 1; r != L'\0'; rsp++) {
  55                 r = *rsp;
  56                 gen++;
  57                 if(matchgen == 0) {
  58                         if(avail == nil) {
  59                                 assert(pool < p->threads + p->nthr);
  60                                 t = pool++;
  61                         } else {
  62                                 t = avail;
  63                                 avail = avail->next;
  64                         }
  65                         t->i = p->startinst;
  66                         if(msize > 0)
  67                                 memset(t->sem, 0, sizeof(Resub)*msize);
  68                         t->next = nil;
  69                         t->gen = gen;
  70                         *clist->tail = t;
  71                         clist->tail = &t->next;
  72                 }
  73                 t = clist->head;
  74                 if(t == nil)
  75                         break;
  76                 ci = t->i;
  77 Again:
  78                 if(ci->gen == gen || matchgen && t->gen > matchgen)
  79                         goto Done;
  80                 ci->gen = gen;
  81                 switch(ci->op) {
  82                 case ORUNE:
  83                         if(r != ci->r)
  84                                 goto Done;
  85                 case OANY: /* fallthrough */
  86                         next = t->next;
  87                         t->i = ci + 1;
  88                         t->next = nil;
  89                         *nlist->tail = t;
  90                         nlist->tail = &t->next;
  91                         if(next == nil)
  92                                 break;
  93                         t = next;
  94                         ci = t->i;
  95                         goto Again;
  96                 case OCLASS:
  97                 Class:
  98                         if(r < ci->r)
  99                                 goto Done;
 100                         if(r > ci->r1) {
 101                                 ci++;
 102                                 goto Class;
 103                         }
 104                         next = t->next;
 105                         t->i = ci->a;
 106                         t->next = nil;
 107                         *nlist->tail = t;
 108                         nlist->tail = &t->next;
 109                         if(next == nil)
 110                                 break;
 111                         t = next;
 112                         ci = t->i;
 113                         goto Again;
 114                 case ONOTNL:
 115                         if(r != L'\n') {
 116                                 ci++;
 117                                 goto Again;
 118                         }
 119                         goto Done;
 120                 case OBOL:
 121                         if(rsp == str || rsp[-1] == L'\n') {
 122                                 ci++;
 123                                 goto Again;
 124                         }
 125                         goto Done;
 126                 case OEOL:
 127                         if(r == L'\n' || r == L'\0' && rep == nil) {
 128                                 ci++;
 129                                 goto Again;
 130                         }
 131                         goto Done;
 132                 case OJMP:
 133                         ci = ci->a;
 134                         goto Again;
 135                 case OSPLIT:
 136                         if(avail == nil) {
 137                                 assert(pool < p->threads + p->nthr);
 138                                 next = pool++;
 139                         } else {
 140                                 next = avail;
 141                                 avail = avail->next;
 142                         }
 143                         next->i = ci->b;
 144                         if(msize > 0)
 145                                 memcpy(next->sem, t->sem, sizeof(Resub)*msize);
 146                         next->next = t->next;
 147                         next->gen = t->gen;
 148                         t->next = next;
 149                         ci = ci->a;
 150                         goto Again;
 151                 case OSAVE:
 152                         if(ci->sub < msize)
 153                                 t->sem[ci->sub].rsp = rsp;
 154                         ci++;
 155                         goto Again;
 156                 case OUNSAVE:
 157                         if(ci->sub == 0) {
 158                                 matchgen = t->gen;
 159                                 if(sem != nil && msize > 0) {
 160                                         memcpy(sem, t->sem, sizeof(Resub)*msize);
 161                                         sem->rep = rsp;
 162                                 }
 163                                 goto Done;
 164                         }
 165                         if(ci->sub < msize)
 166                                 t->sem[ci->sub].rep = rsp;
 167                         ci++;
 168                         goto Again;
 169                 Done:
 170                         next = t->next;
 171                         t->next = avail;
 172                         avail = t;
 173                         if(next == nil)
 174                                 break;
 175                         t = next;
 176                         ci = t->i;
 177                         goto Again;
 178                 }
 179                 tmp = clist;
 180                 clist = nlist;
 181                 nlist = tmp;
 182                 nlist->head = nil;
 183                 nlist->tail = &nlist->head;
 184         }
 185         if(rep != nil)
 186                 *rep = endr;
 187         return matchgen > 0 ? 1 : 0;
 188 }